1. Field of the Invention
The present invention relates to disk drives for computer systems. More particularly, the present invention relates to a disk drive implementing wear prevention in a high frequency access band of tracks.
2. Description of the Prior Art
In disk drives, a head is actuated radially over a disk in order to access a target track recorded on the disk. The head is attached to a distal end of an actuator arm which is rotated about a pivot by a voice coil motor during seek operations. As the disk rotates, an air bearing forms which causes the head to “fly” just above the disk surface while writing magnetic transitions during a write operation, or reading the magnetic transitions during a read operation. The head comprises a slider having an air bearing surface and an integrated transducer, such as a write coil and a magnetoresistive read element.
Decreasing the distance between the transducer and disk surface (fly-height) improves the signal-to-noise ratio in the read signal, thereby enabling higher recording densities (radial tracks per inch and linear bits per inch). However, decreasing the fly-height can deplete the lubricating film that covers the disk surface, particularly if the head remains at the same radial location over an extended period of time. This depletion increases the chance the head will contact the recording surface causing damage and data loss. Designers have implemented wear prevention techniques by dithering the location of the head while the disk drive is idle (not performing read or write operations). However, certain applications may repeatedly access (read or write) data located in a narrow band of tracks over a number of high frequency commands preventing the disk drive from entering the idle mode to perform wear prevention. This can lead to wear in the band of tracks associated with the high frequency accesses.
There is, therefore, a need to reduce wear in a disk drive that performs a number of high frequency accesses to a band of tracks without entering an idle mode.